The present invention relates to an information system which displays information as to a travelable route corresponding to a residual energy state of a vehicle.
Japanese Patent Provisional Publication No. 9-210702 discloses a navigation system which displays energy supply stations on a map when an residual energy quantity of a battery of an electric vehicle becomes smaller than a predetermined level, so that a user of the electric vehicle can reach a proper energy supply station without causing an accident due to battery exhaustion.